Hydraulic valve lifter



y 22, 1955 L. J. VAN SLOOTEN HYDRAULIC VALVE LIFTER Filed March 50, 1955I N V E N TO R flax; J30 $750k); -5-2 #M I ATTO PNEYS HYDRAULIC VALVELIFTER Louis J. Van Slooten, Holland, Mich., assiguor to General MotorsCorporation, Detroit, Mich., a corporation of Delaware This inventionrelates to hydraulic valve lifters for automatically taking up excesslash in the valve trains of internal combustion engines and the like,and particularly to such lifters of the self-contained typefin which thehydraulic fluid is sealed Within the assembly with no provision forv itsreplenishment from any external source during operation. j j

The principal object of the invention is to provide an improvedconstruction for lifters of the aforementioned type comprising agenerally cup-shaped cylinder having a slidably fitted plunger thereinand the open end of the cylinder cup sealed by an expansible bellowswhich is enclosed within the cylinder above the plunger, the oppositeends of the bellows being sealingly connected in a novel manner to theside walls of the cylinder and to a thrust transmitting member laterallysupported by and resting on the plunger, the assembly as a wholeproviding a compact design of few parts particularly adapted to low costmanufacture and assembly.

The means by which this and other objects of the invention are attainedwill be more clearly understood from the following description of apreferred embodiment, having reference to the drawing wherein:

Figure 1 is a sectional view of a portion of an internal combustionengine having a valve operating train incorporating my lifter.

Figure 2 is an enlarged sectional view similar to Figure 1, showing theinternal construction of the lifter.

.Figure 3 is a sectional view through the lifter, taken on line 3-3 ofFigure 2.

Referring now in detail to the drawing, there is shown in Figure 1 anengine cylinder block and crankcase structure designated generally bythe numeral 1 in which is located a working cylinder 2 having the usualpiston 3. Closing the upper end of the cylinder 2 andforming acombustion chamber 4 above the piston is a cylinder head 6. At 7 isapoppet valve controlling communication between a cylinder head port 8and the combustion chamber 4 and having a stem 9 slidably mounted forreciprocation in the cylinder head. In conventional manner, reciprocalmovements ofthe valve 7 are effected by rotation of a cam 11 which issuitably supported in the crankcase 1 and driven in timed relation withmovements of the piston 3. Completing the valve operating train, I haveshown my lifter 12 operatively engaging'the cam 11 and slidablysupported for reciprocation in a lifter bore 13 formed in thecrankcase 1. Upward movements of the lifter are transmitted by the usualpush rod 14 man adjusting screw 16 fixed in one end of the rocker 17,which latter is arranged to oscillate about an axis represented by therocker shaft 18 suitably supported on the cylinder head 6, the other endof the rocker being in driving engagement with'the upper end of thevalve stem 9. A valve return spring 19 having one end secured to thevalve stem and its other end seated against the cylinder head is alsoshown, and serves to maintain the valve in closed position asillustrated in Figure 1.

As shown'in Figure 2 the lifter 12 comprises telescoping United StatesPatent I 2,746,437 Patented May 22, 1956 2 r cup-shaped cylinder andpiston'members 21 and 22 arranged in nesting relation. Between theclosed end of the lifter cylinder 21 and the adjacent end of the lifterpiston 22is a fluid pressure chamber23 which is normally maintainedfilled with fluid for transmitting thrust from the cylinderto the pistonduring opening movements of the engine valve 7. a This pressure chamberincludes a well 24 which opens upwardly into an enlarged diameterportion 26 of preferably greater diameter'than the bore 27 of thecylinder and extending upwardly beyond the lower end of the piston outerperiphery. The lower end of the piston has an extension 28 of reduceddiameter 4 forming a shoulder 29 at its juncture of the main body to thepiston. Loosely-journalled on the extension 28 and having an externalflange 31 rotatably seated against the shoulder 29 is a cup-shaped cagemember 32 whose end wall is provided with one or more apertures 33 whichprovide communication between the interior of the cage member and theportion of the chamber 23 externally thereof. The lower end of the well24 is of smaller diameter than the main portion thereof and formsa loosefit about the lower end of a'piston biasing spring 34 whose upper endloosely embraces the cage member 32 and maintains the flange 31 of thecage seated against the shoulder 29 of the piston. Extending through thebottom wall of the lifter piston and its extension 28 is a fluid supplypassage 36, through which fluid may pass through the interior of thepiston to the pressure chamber 23. A check valve accommodating such flowbut preventing flow of fluid in the reverse or upward direction throughthe passage 36 is provided in the form of a ball 37 which is vof largerdiameter than the passage 36. The seat for this ball 37 is formed by thelower end of the extension 28, and when the ball is in engagement withthis seat and the cage flange 31 is in abutment with the piston shoulder29 only a predetermined small clearance (on the order of a .004.008 in.)exists between the ball and the bottom wall of the cage member. The sidewalls of the cylinder member 21 extend above the operating range of thepiston 22, forming an enclosure 38 whose internal diameter is preferablymade larger than the cylinder bore 27.

The side walls of the piston member terminate at the lower end of theenclosure 38, and resting on the end of the piston side walls is aplug-like member 39 which serves to'transmit piston thrust to and formsa lower seat for the push rod 14. This plug or seating member iselongated as shown, having a flange portion 41 intermediate its endswhich abuts the end face of the piston side walls and a depending hollowskirt portion 42 which extends into and laterally bears against theinternal side wall surfaces of the piston. The flange 41 is of somewhatsmaller diameter than the. external periphery of the piston, whereby itsmarginal extremities are substantially spaced from the internalperiphery of theenclosure 38, and the skirt portion 42 is provided withone or more notches 43 extending from the lower end thereof andterminating in the flange portion 41 to form fluid passages connectingthe interior of the piston with the enclosure 38. Above the flange 41the seating member 39 is formed with an upstanding portion 44 whoseupper end is shown spherically recessed to receive the sphericallyshaped lower end of the push rod 14.

Spaced above the seating member 39 at the open end of the enclosure 38is a ring shaped member 46 which embraces the push rod 14 and has itsinternalperiphery lies the end face of the cylinder side walls. A fluidtight joint between the cylinder member 21 and ring 46 is provided bypress fitting the down-turned outer extremities of the ring flangeportion 47 onto the reduced diameter portion 48 of the cylinder sidewalls. Extending between and abutting the oppositely disposed facesofthe ring 46 and the flange 41 is an expansible bellows 51 which isgenerally tubular inform and has its opposite ends provided with flanges52 and 53 respectively which are spun into external grooves 54 and 55formed on the peripheries of the ring 46 and seating member 39. Toinsure obtaining a fluid tight connection at these points, as well as atthe connection of the ring flange 47 in the groove 48, a fillet 56 ofsolder or any suitable adhesive material is extended around the bottomof each groove as shown.

In operation, lifting movements of the lifter cylinder 21 in response torotation of the cam 11 are transmitted to the lifter piston 22 throughthe medium of the hydraulic fluid which is trapped within the pressurechamber 23 upon closure of the piston passage 36 resulting from the ballcheck valve 37 moving to its seated position at the lower end of thispassage in response to increased fluid pressure in the chamber 23.Continued upward movement of the lifter cylinder is then accompanied byupward movement of the lifter piston which, in turn, transmits thismovement through the push rod seat member 39 to the push rod 14, causingthe rocker 17 to rotate on its shaft 18 and open the engine valve 7against its return spring 19. The spring 19 serves both to close theengine valve and to return the lifter to its initial position after eachlift stroke of the cam. Any Wear or thermal contraction of the partswhich would tend to create an endwise clearance between the upper end ofthe engine valve stem and the cam when the engine valve is in closedposition is taken up by the lifter spring 34 urging the lifter pistonout of its cylinder and the lifter cylinder against the operating faceof the cam. In order that the lifter may also accommodate anylengthening of the valve train resulting from thermal expansion of theparts as the engine heats up in operation, a certain amount of fluidleakage past the lifter piston from the pressure chamber 23 during eachlift stroke is provided for in the fit between the lifter piston and thecylinder bore 27. This leakage fluid is returned to the interior of thelifter piston via the notches 43 in the push rod seat 39. As the volumeof the pressure chamber is increased by the action of the lifter spring34 in urging the piston outwardly of its cylinder after each liftingstroke the resultant pressure drop in the chamber 23 permits the ballcheck valve to leave its seat to the extent permitted by the cage member32 and sufficient fluid then flows downwardly through the passage 36 toreplenish this leakage from the interior of the piston. At the start ofthe next lift stroke the fluid pressure in the chamber again rises,causing the ball check valve to again seat itself and the operatingcycle to be repeated.

Above the flange 41 the cylinder side walls and the bellows 51 provideadditional storage capacity for the hydraulic fluid. This fluid isplaced in the piston 22 and enclosure 38 prior to sealing the ringflange 47 to the cylinder, and after the latter operation is made atfinal assembly no further addition of fiuid is required during the lifeof the lifter. A very compact unit is thus obtained which does notdepend upon any external source of fluid in operation, and by reason ofthe bellows being enclosed within the cylinder member 21 it is protectedagainst accidental damage both during service operations on the engineand handling prior to installation.

Having thus described a preferred structural embodiment illustrating theprinciples and advantages of my invention, minor modifications willreadily suggest themselves to persons skilled in the art. Suchmodifications, however, shall not depart from the spirit and scope ofthe invention as defined by the following claims.

I claim:

1. In a longitudinally extensible thrust transmitting device comprisingslidably interfitted driving and driven members having the side walls ofthe outer member extending longitudinally beyond the corresponding endof the inner member, means forming a fluid sealing closure for the saidend of the inner member, said means being substantially wholly containedwithin the outer member above the inner member and including a seatingmember in direct thrust transmitting coaction with said end of the innermember, a bellows having one end seated on said seating member and aring sealingly securing the other end of the bellows to the outermember, said ring having a portion facing said seating member and inendwise abutting engagement with the bellows.

2. In a longitudinally extensible device having a cylinder member openat one end and a piston slidably fitting the cylinder member and havingits end nearest the open end of the cylinder member terminating asubstantial distance from said cylinder open end, said piston beinghollow and provided with a plug having a flange portion abutting saidend of the piston, an upstanding portion extending toward the cylinderopen end and a depending portion extending into and laterally bearing onthe internal side wall surfaces of the piston, a tubular bellows withinthe cylinder member loosely embracing said upstanding portion andsealingly secured at one end to said flange, and a ring sealinglysecuring the opposite end of the bellows to the open end of the cylindermember and having its internal diameter sufficiently large to freelyreceive said upstanding portion, said ring having a transverselyextending seating surface in end-wise abutting engagement with a portionof its adjacent end of the bellows.

3. In a hydraulic lifter having cup-shaped piston and cylinder membersin slidably nested relation and forming a fluid pressure chamber betweentheir respective end walls, said piston member having its side wallsterminating within the cylinder member in longitudinally spaced relationfrom the open end of the cylinder member side walls, and sealing meansfor the open end of the cylinder member substantially wholly recessedwithin the cylinder member including an elongated piston thrusttransmitting member having a flange intermediate its ends in abutmentwith the open end of the piston member, a ring having a portion pressfitted over the open end of the cylinder side walls and a longitudinallyexpansible bellows having its oppositely disposed ends abutting theoppositely facing portions of said ring and flange, said thrusttransmitting member having an end portion depending into the pistonmember from said flange and laterally supported by the side walls of thepiston member.

4. In a hydraulic lifter having cup-shaped piston and cylinder membersin slidably nested relation and forming a fluid pressure chamber betweentheir end walls and an enclosure for the storage of fluid outwardly ofthe piston end wall, said piston member having its open end terminatingwithin the cylinder member in spaced relation from the open end of thecylinder member, a push rod seating member defining a relatively largeportion of said enclosure adjacent said pressure chamber, said seatingmember having oppositely disposed end portions slidably fitting the openend of the piston member and extending therefrom toward the open end ofthe cylinder, respectively, and having a flange intermediate its saidportions abutting the piston outer end, said flange and slidably fittingend portions of the seating member having connecting passages providingfluid communication between the interior of the piston member and theinterior of the cylinder member above the piston member, and anexpansible bellows loosely surrounding said seating member extendingportion, said bellows being wholly contained within the lateral confinesof said cylinder member above the piston member and having itsoppositely disposed ends sealingly secured to said flange and to theopen end of the cylinder member, respectively.

5. In a self-containing-fluid type hydraulic valve lifter comprisingslidably nested cylinder and piston cups having their respective endwalls defining a fluid pressure chamber and the interior of the pistoncup constituting an adjacent reservoir for fluid entering and leavingsaid chamber, said cylinder cup having extended side walls forming anenclosure outwardly of the piston cup, a ring member having a flangeresting on the open end of the laterally bearing on the internal sidewall surfaces of the piston cup, said flange having its lateralextremities spaced from side walls of the cylinder cup and provided withpassage means in fluid communication with said reservoir, an annularmember forming a seat in oppositely disposed spaced relation to saidflange, and a tubular bellows having its opposite ends abutting saidseat and flange, said ring and annular members each having a peripheralexternal groove facing the internal side wall surfaces of the cylindercup, said cylinder cup having a peripheral external groove adjacent itsouter end, said annular member having a flange portion overlying theouter end of the cylinder cup and terminating in said cylinder cupgroove, and said bellows having flange portions at its opposite endsterminating in the respective grooves of said ring and annular members.

6. In a hydraulic lifter having cup-shaped piston and cylinder membersin slidably nested relation and forming a fluid pressure chamber betweentheir respective end walls, the interior of the piston member forming anadjacent reservoir for fluid entering and returning from the pressurechamber, an expansible bellows disposed wholly piston cup and a portiondepending from the flange and within the cylinder member between theopen ends of the piston and cylinder members, said bellows defining withthe internal periphery of the cylinder member an extension of saidreservoir, an annular member fixedly secured to the cylinder member openend and in abutment with the end of the bellows nearest the open end ofthe cylinder member, said annular member having an external peripheralgroove into which said end of the bellows is crimped and sealinglysecured, and a push rod seating member having an upstanding portionloosely received within the bellows and an adjacent flange portionresting on the open end of the piston member, said flange portion beingin abutment with the opposite end of the bellows and having an externalperipheral groove into which said opposite end of the bellows is crimpedand sealingly secured, said seating member having a portion dependingfrom saidflange portion and slidably fitting the internal periphery ofthe piston member, said flange and depending portions of the pistonmember being provided with connecting passages maintaining fluidcommunication between said reservoir and reservoir extension.

References Cited in the file of this patent UNITED STATES PATENTS1,930,554 Hallett Oct. 17, 1933 2,096,257 Moorhouse Oct. 19, 19372,153,097 Moorhouse Apr. 4, 1939 2,376,182 Peterson May 15, 19452,553,756 Engemann May 22, 1951 2,634,714 Randol Apr. 14, 1953 FOREIGNPATENTS 988,202 France Aug. 24, 1951

